LE TISSU APICAL DES GONADES DU DORYPHORE,LEPTINOTARSA DECEMLINEATASAY (COLEOPTERA: CHRYSOMELIDAE)

Abstract

A somatic tissue, the apical tissue exists both in the ovaries and the testes of the Colorado Beetle from the embryonic stage till the end of the imaginal stage. This tissue is always situated near the primary gonia and consists of electron-lucent and electrondense cells that probably represent different physiological states of a single cellular type. Electron-lucent cells are characterized by an important granular endoplasmic reticulum with swollen cisternae filled with products of microfibrillar structure, and ribosomes grouped in polysomes. These cells evolve into electron-dense cells more rapidly in the testis than in the ovary. In the electron-dense cells, the ribosomes are isolated, the rough endoplasmic reticulum shows a particular fingerprint-like disposition. In these cells, the secretory products, concentrated in large granules of a glycoproteic nature, are extruded in the intercellular spaces and enlarge them. Moreover, they should induce cytolysis of the cystic cells and of the neighbouring gonia. Gonia and cystic cells are finally reduced to cellular fragments (mitochondria, ribosomes and autophagic vacuoles) which would be compared with ovarian nutritive cords. The 'nutritive cords' so formed, appear at the 2nd larval stage in the testis and at the nymphal stage in the ovary and are inserted between the cysts. Indirectly, the apical tissue thus should have a nutritive role.

Ovogenèse et transmission des bactéries symbiotiques chez le charançonSitophilus oryzaeL. (Coleoptera: Curculionoidea)

“…Chez le doryphore Leptinotarsa decemlineata, un tissu apical dans les ovarioles a bien été décrit, mais il ne renferme pas de symbiotes (Richard-Mercier 1981). Mansour (1930) considère que la contamination des tout jeunes ovocytes se fait à partir des symbiotes des bactériomes apicaux.…”

Differentiation of male reproductive system inOryctes rhinoceros (Coleoptera: Scarabaeidae)

“…According to Gundevia and Ramamurthy (1974) Verson's cells encircle apical cell and are nutritive in function. The ultrastructural studies on apical cell (Menon 1969;Richard-Mercier 1981) also show that they are nutritive in function. Apical cell is not observed in Tribolium castaneum (Murad and Ahmad 1977) and in P. punctatipennis (Inamdar and Joshi 1986).…”

“…A detailed study on the Verson's cells, aberrant spermatozoa and male accessory glands in Hydrophilus olivaceus has been carried out by Ramamurthy (1974, 1977) and Smrz (1978) studied the spermatogenesis in Agonum assimile. Richard-Mercier (1979, 1981 reported the light and electronmicroscopic work on apical cells and evolution of germinal cells in Leptinotarsa decemlineata. Oryctes rhinoceros, a member of the family Scarabaeidae is a major pest of coconut palm.…”

Ultrastructure du tissu apical testiculaire du doryphoreLeptinotarsa decemlineataSay (Coléoptère: Chrysomélidé): étude autoradiographique et cytochimique / Ultrastructure of the apical testicular tissue of the doryphoreLeptinotarsa decemlineataSay (Coleopterae: Chrysomelidae): an autoradiographic and cytochemical study

“…'absence de mitose dans ce tissu entra'ine progressivement une reduction de son importance au cours du developpement post-embryonnaire; neanmoins, il est toujours present chez ! 'imago senescent [15]. Les [16).…”

“…Les [16). L'ultrastructure des cellules apicales, caracteristique des cellules secretrices, evolue au cours de Ia vie larvaire [15). Nous avons entrepris l'etude cytochimique et autoradiographique afin de preciser Ia nature des secretions de Ia cellule apicale.…”